The determination of the size of the binding site of an immunoglobulin and the investigation of the nature of forces involved in the binding process requires a large number of ligands. In the case of carbohydrate specific antibodies, ligands constitute series of homologous carbohydrate derivatives which are invariably obtained by sophisticated chemical syntheses. In addition to mono and oligosaccharides related to the natural antigen, we synthesize modified ligands. To those belong molecules having, for example, certain hydroxyl groups replaced by functions which modify the binding pattern, thus allowing to draw conclusions about the importance of various forces in the binding process. To investigate the possible role of hydrogen bonding in the interaction of carbohydrate antigens and antibodies our endeavors are concentrated at synthesizing ligands bearing deoxy and deoxyfluoro functions. Among these, of special interest are derivatives of methyl-alpha-D-glucopyranoside bearing bulky substituents at position 2 or 3. From the mode of interaction of this type of ligands we expected to be able to draw conclusions about the spatial accessibility of the highest-binding subsite.